Answer:
a. Future expectations.
b. Income.
c. price of a related good
d. consumer preferences.
Explanation:
Remember, there are several factors that affects demand, such as:
In example:
a. The current demand will decrease because of expectations of an improved model of the preferred phone.
b. The purchasing power to buy a more expensive was increased because the grandparents gave the individual $500.
c. The price of data packages a complementary good decreases, leading to more demand for phones.
d. The referral of a friend influences interest, leading to a purchase of the cell phone.